Game racket construction



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Bf y f F ATRNE April 2, 1963 Filed Dee. 17, 1958 YOSHIAKI ITAKAHASH]GAME RUKET CONSTRUCTION 3 Sheets-Sheet 3 IN I/ENTR 7KA HA SHI hyam/A K fTTRNEY United States Patent Office 3,083,968 Patented Apr. 2, 19633,083,968 GAME RACKET CONSTRUCTIN Yosiliaiti Takahashi, 46 1-chomeike-maehi, Nagoya City, Japan Filed Dec. 1.7, 1958, Ser. No. 780,991 1Claim. (Cl. 273-73) This -invention relates to game rracket constructionand more particularly to the construction of a light, strong, resilient,warp-proof badminton racket suitable for mass production.

Heretofore, for the manufacture of rackets, wood r other material hasbeen used and this required hand-finishing to give a delicate andvariable shape to the frame and to other parts -in order to improveswing-balance and also to maintain the strength. Hence, not only is it avery ineflicient method, but also, it is difficult to obtain a uniformquality at moderate price.

An object of the invention is to provide ya game racket construction andmanufacturing method wherein, the three-forked par-t of the frame ispressed and fixed by means of a synthetic resin t-o provide a strong,resilient, warp-proof -and durable racket.

Another object of the invention is to provide a game racket construction`and manufacturing method wherein the frame and the shaft of the racket`are made -separately then joined in an unbreakable manner.

A further object of the invention is to` provide a racket wherein theshape and direction of the gut of the frame is made so as to obtain astrong, resilient and warp-proof racket.

The invention also contemplates providing a racket wherein constructionof the racket grip is contrived so as to increase its strength andregulate its swing-balance.

Other objects and advantages of the invention will become apparent fromthe following description of the invention.

The Vaccompanying drawings lare illustrative 4ernbodiments of theinvention in which:

FIG. 1 shows a racket wherein the frame and the shaft of the racket aremade of one single piece of material;

FIG. 2 is a front elevation and diagram showing the frame part; Y

FIG. 3, a front elevation of one embodiment of a three-forked part inanother example;

FIG. 4 is another embodiment of a three-forkedV part;

FIG. 5 is a front elevation of a racket constructed laccording to theinvention showing details of construction;

FIG. 6 shows a racket wherein the frame land shaft are made separately;

FIG. 7 is a front elevation of another embodiment of the invention`similar to that depicted in FIG.y v6;

FIG. 8 is a sectional view of the shaft in FIG. 7 on the line 1 1;

FIG. 9 is a front elevation of `a frame part;

FIG. i0 is a sectional view of the frame in FIG. 9 on 2 2;

FIG. ll is a sectional View of the shaft in FIG. 9 on 3 3;

FIG. 12 is another sectional view of the racket in FIG. 9 on 4 4;

FIG. 13 is a sectional view similar to FIG. 10 of another embodiment ofthe invention;

FIG. 14 is a sectional view of another practical example correspondingto FIG. 11;

FIG. 15 is another front elevation of the racket `according to thisinvention;

FIG. 16 shows an embodiment of the invention wherein 4the frame and theshaft of the racket is made of a synthetic resin;

FIG. 17 is a side view of FIG. 16;

FIG. 18 is -a sectional view of FIG. 16 on 5 5;

FIG. 19 is a front elevation of another embodiment;

FIG. 20 is a sectional view of FIG. 19 on 6 6;

FIG. 21 shows the grip part of the racket in front elevation;

FIG. 22 is a sectional View of FIG. 21;

FIG. 23 is a sectional view of the FIG. 21 on 7 7;

FIG. 24 is a front elevation of a racket frame;

FIG. 25 is a sectional view of the FIG. 24 on 8 8; FIGS. 26 to 29 areother embodiments similar to FIG. 25;

FIG. 30 is a sectional view of the frame according to still anotherembodiment of lthe invention;

FIGS. 31 and 32 show other embodiments similar to FIG. 30.

Referring to the drawings for more specific details of the invention,the rackets shown in FIGS. 1-5 are shaped of a light, solid and straightmaterial of metal, wood or bamboo (bar or pipe) and these are bent andboth the shaft I and the frame 2 shaped into a single and continuousshape; the lower end of the shaft 1 is fitted with a grip 3 and on thethreedforked part extending from the upper part of the shaft 1 to theground i.e., bottom 4 of the frame, synthetic resin material such asacetylcellulose, a shock resistant styrol, etc. is pressed by means of ametal moulding.

According to this invention, since the three-forked part of the frame ispressed yand fixed with a synthetic resin, there is no danger ofbreakage and no need to provide the shaft with rivets; the shaft is thuspossessed of both durability and the appropriate resilience. Themanufacturing method of the racket according to this invention, dependsupon a simple process such las bending of metal or other material andmoulding of a synthetic resin and therefore it is well suited for massproduction of uniform quality with low manufacturing costs. If the partapplied with a synthetic resin extends to the upper part of the frameground 4, as shown in FIGS. 1 and 2 it will be stronger and moreresilient but, if desired, it may be applied only to the upper end ofthe shaft 1 and the frame ground 4, as shown in FIG. 3. Furthermore, ifthe three terminal edges of the applied synthetic resin are made into abig neck 6 as shown in FIG. 4, a better result with the synthetic resincan be obtained. It is well to select especially a shock resistantsynthetic resin in order to get a more resilient racket. If necessary,the upper end of the shaft may be fitted with rivets similar to thoseshown in FIG. 6. Moreover, if the synthetic resin is applied not only onthe three-forked part 5 but also on the whole surface of the frame 2,the racket will look like that in FIG. 5 and different results asmentioned above can be had. If the sectional area of the frame is madesmaller, sufficient strength can be obtained `by properly distributingthe synthetic resin on every surface of the frame of the racket; thusswing-balance is easily regulated by means of said synthetic resin.

In the above description, the frame and the shaft of the racket are madeof a single piece of homogeneous material. However, it is desirable thatthe frame be made of `a light land strong material `and the shaft, of astrong and resilient material, Therefore, the frame and the shaft needto be shaped separately. From this viewpoint, those rackets shown inFIGS. 6-.15 have been designed, in which, as in FIG. 6, a straightshaped material such as bar, or pipe of a light metal, wood or b-amboois bent into a racket frame 2; and separately from' this, a straight baror pipe of light alloy treated With a special hardening process and thusmade into a strong and resilient material, is shaped into a shaft 1. Thelower end of the frame 2 and the upper end of the shaft are joinedtogether by appropriate means to form the joined part 7. As shown `inFIG. 6, the synthetic resin is `applied and pressed on the surfaces ofthe upper part of the shaft 1, the joined part 7 as well as the ground 4of the frame; and a grip 3 is fitted to the lower end of the shaft 1. Asfor the construction of the joined part 7 of the frame 2 with the shaft1, the one shown in FIG. 6 consists of the upper part P of the shaft 1inserted into a gap of two perpendicular parts h, h1 on the lower end ofthe frame 2. If necessary, the upper end P and said perpendicular partsl1, h1 may be clamped together by means of rivets 9 and 9', then thedevice placed into `a metal mould where the plastic reinforcement 8 ismolded around junction 7. As a matter of fact, parts lz, h1 and P may betied together by means of wire instead of riveting. This construction ofthe joined part is particularly suited when a metal bar is used for theshaft 1 resulting in a large surface area of the joined part; here, theapplication of the synthetic resin can be performed easily and solidly.This is the main advantage of this method. For the joined part shown inFIGS. 7-8, a pipe is used for the shaft l; inside the mouth on the upperend of the pipe shaft 1 are inserted two perpendicular parts h2, h3 onthe lower end of the frame 2. If necessary, the joined parts are clampedwith rivets 9, 9'. The racket of this construction is extremely solidand resilient and the manufacturing process is very simple. Therefore,this racket is well suited for mass production.

As mentioned above, the drawings in FIGS. 9-14 illustrate themanufacturing method whereby the joined part may be either pressed ornot and shaped by means of a synthetic resin but in any case, obtaininga solid joined part. In FIGS. 9-12, a shaped material (rolled orotherwise) of a light metal such as aluminum alloy, etc. is bent in sucha way that the channel 10 is extruded outside to form the frame 2 andtwo perpendicular parts h4, h on the lower end of said frame, are weldedtogether (FIG. l1). Said perpendicular parts h4, h5 are inserted intothe mouth on the upper end P3 of the shaft 1 made of a pipe or aresilient material such as aluminum alloy, etc. and by applying externalforce to the shaft 1 from outside of the upper end P3, the channel ispushed and inserted into the outside wall of said upper end P3. Both theconcave channel 131 and said upper end P3 into which said parts areinserted are rivetted together -by means of `the rivet (shown as adotted line in FIG. 1l) with the perpendicular parts h3, 115 betweenthem. The joining of the frame with the shaft thus obtained is so strongthat it needs no other strengthening means. However, it is desirablethat the joined part 7 is fitted with a tube of a synthetical resin orsome other material on its circumference so as to cover the joined part.In the drawing, 14 shows a gut hole. FIGS. 13 and 14 show another modeof the joined part formation, wherein the frame 2 formed by bending ashaped material of a rolled light metal such as aluminum alloy, etc. tothe `direction where the channel 10 is extruded outside. In the gapbetween two perpendicular parts h4, 115 on the lower end of said frameis inserted the upper end of the shaft, provided with a cavity adaptedto the shape of the channel 15 inside and between said perpendicularparts h4, h5; the shaft is also shaped to produce a rolled part 18supported by the opposed edges 17, 17 of said perpendicular parts h3,h5. The shaft is made of a resilient pipe of a light alloy pressed andshaped, and the perpendicular part-s h3, h5 of the frame are fastenedtogether by means of a rivet (shown as dotted lines in FIG. 14) with theupper end P3 of the shaft between them. Hence, as shown in FIG. 14, theupper part P3 of the shaft 1 has a rolled part 18, which has aresilience against the fastening power of the rivet 12 so that thejoined part thus made is extremely strong. The modes described in FIG. 9and below may be used without lapplying a synthetical resin to thejoined part 7. However, if a synthetic resin is applied to it, it willbe endowed with a better resilience as well as warp-proof properties.The racket, the joined part of which is thus made has superiority overother rackets, particularly where the frame and the shaft are made of asingle material, because it is difficult to find in a single material`both strength for the frame and resilience for the shaft. Here becauseythe frame and the shaft are made separately of materials havingdesirable properties, the very best racket is produced. Moreover, thejoining mode is very simple and provides a very solid joint.

In the example shown in FIG. l5, the synthetic resin is applied not onlyon the joined part 7 above the shaft 1 and the outer surface of theframe ground but also on the whole surface of Ithe frame 2. In this way,not only the above-mentioned different results can be obtained but alsoeven if the sectional area is reduced, a sufficient strength can beobtained and a better xing of the synthetic resin insured. Moreover, asit enables appropriate distribution of the synthetic resin on every partof the frame, the swing-balance of the racket is easily regulated bymeans of said synthetic resin.

FIGS. 16-20 explain a manufacturing process of the racket, wherein theframe 2, the shaft 1 and the grip 3 are shaped, each one separately andthe upper end of the shaft 1 is inserted into a hole made on the lowerend of .the frame 2 and held by means of an adhesive material and at thesame time fastened with a pin 20. The lower end of the shaft 1 isinserted into the hole 21 of the grip 3 and held with an adhesivematerial and fastened with a pin 22. The frame 2 may `be shaped with asynthetic resin or may include a metal bar, pipe or shaped material inits center. Moreover, in the latter case when a metal frame material isincluded, the synthetic resin may be applied approximately on the lowerhalf-part or on the whole surface of the frame. The shaft 1 may beformed by means of a synthetic resin reinforced with a glass wool orcloth, or a built-up pipe of the same material, or a pipe or bar ofaluminum alloy. Moreover, the front and the back ysurfaces 23 of theframe 2 are provided with intermittent long and shallow channels 25, 25separated with a partition wall 24 so as to lighten the frame 2 as wellas to regulate the length and the depth of said channels 25, 25', etc.and also to ameliorate swing-balance of the racket. As shown in FIG. 18,because of this special sectional shape of the frame 2, the strength andwarp-proof quality of the racket are insured. In this case, if morelightness is required, a continuous, long and shallow channel 26 may beprovided in the shape of the frame 2 as shown in FIG. 19. In the abovedrawings, gut hole 14 is shown in channel 27, the channel being made onthe outer circumference of the frame.

As mentioned above, the frame and the shaft are made, each oneseparately and the upper and the lower ends of the shaft are insertedrespectively into the lower end of the frame and into lthe upper end ofthe grip and fastened together to complete the racket. Thismanufacturing process is extremely simple and suited for mass productionof a uniform quality.

FIGS. 21-23 relate to a grip part of the racket. Usually severalprocesses are needed for the finishing of the shaft part and the grippart and still uniform strength can not be obtained, while in thepresent invention, the shaft is made of a pipe or bar of a light alloyand by means of a synthetic resin shaping, the shaft and the grip aremade instantly into a combined structure of uniform strength. The shaft1 is made of a pipe or bar of aluminum alloy, superfcially treated withnickel plating. The lower end of said shaft is appropriately -cut withconcave nicks. Said lower end is inserted inside the metal mould and bymeans of a synthetic resin material such as acetylcellulose, a shockresistance styrol or urea resin, the grip 3 and shaft 1 are shaped byjet or press into a single structure.

As shown in FIGS. 2l and 23, the grip 3 is provided with concave andconvex nicks 28 for friction on the outside and inside is a cavity 31formed with a thick wall 30. The ribs 29 protrude out of the inner wallalong the length of the grip and the open lower circumference of Ithehandle is provided with a protruding baud 32 to which is iitted ya cover33 of a hard polyethylene resin, etc. Since the racket is constructedlas mentioned above, it is not only suitable `for mass production, butalso the combination of the grip with the shaft is very strong and ifthe cover is taken oil?, appropriate weighting material can be putinside to regulate the swingdbalance of the racket as well 'as to adaptthe tare of the racket with the user.

FIG. 24 shows the results of study on the sectional shape `of the frame,and FIG. Shows a cross section of the frame 2 in FIG. 24. Said frame 2is composed of an outside part 36 exposing a wide part 34 and a thickpart 35 on both the front and the b-ack surfaces of the racket. Theinside par-t 39 comprises a thick part 37 facing inwardly and nearly atrigh-t angle to said outside part 36, thus having a T-shape crosssection. The wide part 3S of said inside part 39 is provided with gutholes 40 nearly at right angle -to the gut stringing surface of theracket. As shown in FIG. 25, the gut hole 40 provided with yan arch 41is preferably narrow in the center, becoming gradually thick toward bothopen ends. In that case, the breakage of the gut is much reduced. In theabove construction, the frame having a T-shape cross section isextremely strong for all kinds of external force, and the racket gutholes are made lat right angle to the gut Stringing surface so that themetal mould for shaping the frame with a synthetic resin can be easilymade.

Moreover, as the gut can be easily passed through the holes, itsStringing operation can be performed with increased efli-ciency and, asa matter of fact, consumption of the gut can be reduced. Even if the gutis tightly strung, no warping of the frame will occur with saidconstruction. FIGS. 26-28 show another frame having a T-shape crosssection, in which in FIG. 26, the outside part 36 and the inside part 39are shaped, each one separately and the inside part 39 is fastened withthe outside part 36.

FIGS. 27 `and 28 show the T-shape cross section shaped so that the metalmaterial part 42 is enveloped with a synthetic resin 43. As shown inFIG. 29, the gut hole 40 having appropriate inclination to the gutStringing surface and another gut hole 40' having a reversed inclinationare made alternately. This is also very useful for reducing warping o-fthe frame due to Stringing.

FIGS. -32 show ano-ther `cross section of the frame in which FIG. 30shows `a frame having nearly C-shape cnoss section, and `between twoedges 44, 44 exposed on the front and `the back surfaces, is riveted across arm 45, =a plurality of said cross arms 45 are fitted all aroundthe frame at appropirate intervals and provided with a concave channelnearly in center. In the drawings, 47 shows the gut. Owing to thisconstruction, the frame is made very |light and as the cross arm 45 isinserted and fitted between the edges 44, 44', not 60 only is it verystrong bu-t also stringing is very easily accomplished. If concavechannel 46 is provided in the center of the cross arm 45, the damage ofthe gut will be much more reduced; at the same time as the gut goessliding into said concave channel, its own traction in the channelduring Stringing provides a tight and a smothly strung surface formed bythe gut. Further, in FIG. 30, said cross yarm 45 is covered with acylinder 49 having a concave part 48 in the center, which is rotatablearound the outer circumference of the former, by this means, the fittingof the gut 47 is made easier and the damage due to friction is reducedeven more. Furthermore, FIG. 32 shows the case when the edges 44, 44tare turned yto the outside of the racket and a gut hole 50is made inthe wall thus providing a stronger frame.

The present invention may be embodied in other specific forms withoutdeparting from the spirit thereof. It is therefore desired that thepresent embodiments be considered in all respects as illustrative andnot restrictive, reference being had to the appended claim rather thanto foregoing description to indicate the scope of the invention.

What is claimed is:

A game racket, comprising in combination,

a T-shaped cross-sectional length of thin, tubular material shaped atits central portion as an ellipse -dening a racket frame with the wideportion corresponding to the roof of the T being towards the outside ofsaid frame, the ends of said length being outwardly bent in the plane ofthe long diameter `of said ellipse;

an elongated hollow member, one end of which engages said bent ends -byreceiving said bent ends in an open mouth at said yone end of saidhollow member;

fastening means fastening said bent ends and said member;

a grip member attached at the lower part of said hollow member;

a molded plastic reinforcing member encompassing the junction of saidhollow member, said fastening means and said ends and extendingpartially around said ellipse; and

hourAglass shaped `aperture walls extending through .the inwardly facingnarrow portion corresponding to the center bar of the T, said wallsforming gut-holes.

References Cited in the le of this patent UNITED STATES PATENTS1,173,588 Larocque Feb. 29, 1916 1,470,878 Robinson Oct. 16', 19231,606,022 Gallaudet Nov. 9, 1926 1,637,583 Norton Aug. 2, 1927 1,862,581Robinson June 14, 1932 1,937,787 Robinson Dec. 5, 1933 2,099,735 HallNov. 23, 1937 2,141,824 Ranger Dec. 27, 1938 2,626,804 Robinson Jan. 27,1953 FOREIGN PATENTS 522,222 Great Britain June 12, 1940 162,109Australia Mar. 22, 1955

